After a billet having a diameter smaller than the inner diameter of a container is sandwiched between an extrusion stem and a die and loaded into the container, when the billet is pressed against the die by the extrusion stem within the container, i.e., upset, the billet is crushed and air between the container and the billet is compressed. The extrusion stem and the container are slightly retracted to discharge the compressed air to the outside of the container and the above-mentioned compressed air is drained through a gap between the die and the container, and then, the container and the extrusion stem are advanced again to start extrusion. A degassing step of draining the compressed air in this manner is referred to as a burp cycle and due to this step, there occurs a step wasteful to the extrusion cycle.
In this method, when deaeration is performed in the burp cycle and the container is pressed against the die, air remains at the atmospheric pressure in a thin layer like a skin between the inner surface of the container and the outer surface of the billet, indicating that sufficient deaeration is not performed.
As a conventional deaeration device of an extrusion press device capable of easily and securely removing the residual air at the time of extrusion of a billet, there is such a device disclosed in, for example, Patent Literature 1, Patent Literature 2, and Patent Literature 3.
In Patent Literature 1, a method is described, by which air within a container is sucked and deaerated through an exhaust hole by comprising a container liner provided with a protrusion in the shape of a ring on the stem side end surface of the container into which a billet is loaded and a two-split seal block that can be opened/closed in a direction crossing the axial direction of the extrusion stem and which has an exhaust hole through which air that remains within the container is discharged, and causing the seal block to come into close contact with the outer circumferential surface of the ring-shaped protruding part and the outer circumferential surface of the extrusion stem at the same time to seal when closing the seal block.
In Patent Literature 2 or 3, a method is described, by which air within a container is sucked and deaerated through an exhaust hole by comprising a container liner provided with a protrusion in the shape of a ring on the stem side end surface of the container into which a billet is loaded and a two-split seal block that can be opened/closed in a direction crossing the axial direction of the extrusion stem and which has an exhaust hole through which air that remains within the container is discharged, enabling the seal block to come into close contact with the side end surface of the ring-shaped protrusion and the outer circumferential surface of the extrusion stem at the same time via a seal member pasted to the seal block when closing the seal block, and causing a pressing means to press the seal member pasted to the ring-shaped protrusion side of the seal block against the side end surface of the ring-shaped protrusion in the extrusion direction to seal.
Then, any of the above-mentioned conventional deaeration devices is configured so that each of the two-split seal blocks moves in both opposite directions along a guide attached to the upper part and the lower part of the container end surface on the extrusion stem side and opens and closes (horizontal movement in both directions on the extrusion press operation side and the opposite side of the operation side). Further, the retracted position when the seal block is released is set to a position where there is no interference with a billet loader that mounts a billet to be loaded into the container and replacement of the container liner with another is not impeded.
A billet is supplied into the container of the normal extrusion press device by a billet loading means after retracting the extrusion stem upon composition of extrusion and moving the billet loader that mounts the billet into a gap between the end surface of the container and the end surface of the retracted extrusion stem.
In the extrusion press device that supplies a billet into the container using a direct type billet loader that supplies a billet to the extrusion press device in a direction crossing the axis of the extrusion press and in a direction horizontal with the axis and which uses the conventional deaeration device configured as described above, when the billet loader is provided on the operation side of the extrusion press or the opposite side of the operation side, the billet loader is also arranged in a position where interference with the deaeration device is avoided.
In order to avoid interference between the billet loader and the deaeration device, it is necessary to secure a gap by extending the extrusion stroke, and therefore, the facilities increase in size and at the same time, the extrusion cycle time is lengthened.
Further, a billet is transferred to and installed on the billet loader by a billet transfer device and a billet carrier is also arranged in a position where interference with the deaeration device in a direction crossing the axis of the extrusion press is avoided.
In order to avoid the interference between the billet transfer device and the deaeration device, it is necessary to lengthen the moving stroke to the extrusion press device of the billet loader, and therefore, the facilities increase in size and at the same time, the billet supply time is lengthened. Then, an increase in size of the facilities impedes the pace productivity.
In order to supply a billet into a container of a rear loading type short stroke extrusion press device, in which after extrusion is completed, the extrusion stem retracts and then moves to secure a gap through which a billet is supplied, a direct type billet loader is used mainly, which comprises an inserter (inserting means) of a billet and performs loading in a direction crossing the axis of the extrusion press device and at the same time in a direction horizontal with the axis.
When the conventional deaeration device is used in the rear loading type short stroke extrusion press device configured as described above and the billet loader is provided on either the operation side of the extrusion press device or the opposite side of the operation side, the billet loader is also arranged in a position where interference with the deaeration device is avoided.
In order to avoid the interference between the billet loader and the deaeration device, it is necessary to secure a gap by extending the extrusion stroke, and therefore, the facilities increase in size and at the same time, the extrusion cycle time is lengthened.
Further, a billet is transferred to and installed on the billet loader by the billet transfer device and the billet carrier is also arranged in a position where interference with the deaeration device in the direction crossing the axis of the extrusion press device is avoided.
In order to avoid the interference between the billet transfer device and the deaeration device, it is necessary to lengthen the moving stroke to the extrusion press device of the billet loader, and therefore, the facilities increase in size and at the same time, the billet supply time is lengthened. Then, an increase in size of the facilities results in excessive occupation of the installation area and the space productivity is impeded.
A billet is supplied into the container of a front loading type short stroke extrusion press device by retracting the extrusion stem and the container upon completion of extrusion, moving forward the billet loader that mounts the billet into the gap between the die side end surface of the container and the die end surface, causing the billet to be sandwiched between the end surface of the extrusion stem and the die end surface by moving forward the extrusion stem, and then moving forward the container.
Then, a billet is supplied into the extrusion press device by using a direct type billet loader capable of moving in the direction crossing the axis of the extrusion press, comprising a clamper (gripping means) of the billet, and capable of moving in the horizontal direction, and the billet loader is provided on either the operation side of the extrusion press device or the opposite side of the operation side.
A billet is transferred to the billet loader by the billet transfer device and the billet transfer device is also arranged in a position where interference with the deaeration device is avoided and in parallel with the axis of the extrusion press device.
In this case, in order to avoid interference between the billet transfer device and the deaeration device, it is necessary to lengthen the moving stroke of the billet loader to the extrusion press device, and therefore, the facilities increase in size and at the same time, the billet supply time is lengthened. Then, an increase in the size of the facilities impedes the pace productivity as a result.
Further, the container cylinder is attached to the main cylinder side so as not to interfere with the billet loader and at the same time, provided in a pair on both the outsides of the extrusion press so as not to interfere when the container is replaced with another. With such a configuration, it is not possible to avoid interference between the deaeration device and the rod of the container cylinder.
Furthermore, in the short stroke extrusion press device of this type, in order to avoid interference between the outer diameter of the billet and the container inner diameter when the billet is inserted into the container, the inner diameter of the container is set larger than that of the extrusion press of other types. Because of this, there used to be the possibility of a larger amount of air involved in the billet at the time of upset of the billet.